CWE 64

Windows Shortcut Following (.LNK)

Weakness ID: 64 (Weakness Variant)

Status: Incomplete

Description

Description Summary

The software, when opening a file or directory, does not sufficiently handle when the file is a Windows shortcut (.LNK) whose target is outside of the intended control sphere. This could allow an attacker to cause the software to operate on unauthorized files.

Extended Description

The shortcut (file with the .lnk extension) can permit an attacker to read/write a file that they originally did not have permissions to access.

Follow the principle of least privilege when assigning access rights to files. Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

Weakness Ordinalities

Ordinality

Description

Resultant

(where the weakness is typically related to the presence of some other weaknesses)

Under-studied. Windows .LNK files are more "portable" than Unix symlinks and have been used in remote exploits. Some Windows API's will access LNK's as if they are regular files, so one would expect that they would be reported more frequently.